Rudeness definitely has a place in professional sport. Timed well and done with the right mix of comedy and competitiveness, it can add to the entertainment of any sporting clash. If it starts up some tense verbal sparring between two tightly wound opponents, all the better.

However, sometimes a competitor takes an insult way too far. Sometimes something is said that is so unpleasant and excessive, it leaves everyone gobsmacked. Take this effort from Nick Kyrgios, for instance.

This is probably sport's ultimate "too far" moment. With Mick McCarthy manager of the Republic of Ireland and Roy Keane their star player, things went well for the Green Army. On the pitch, that is.

Unfortunately, resentment between the two men was building off it. Then, ahead of the 2002 World Cup, Keane suddenly let all his frustrations with Mick come out.

He apparently told his manager: "I didn’t rate you as a player, I don’t rate you as a manager, I don’t rate you as a person". Ouch. He then went on a huge, expletive-laden rant about him.

Keane was meant to have concluded: "I’ve got no respect for you. The only reason I have any dealings with you is that somehow you are the manager of my country. You can stick it up your b*llocks". Right.